1. Technical Field
The present invention relates to an improved data driver.
2. Description of Related Art
Computers have evolved during the past several decades from large bulky slow machines used primarily by businesses and scientists to process large accounting and mathematical calculations to smaller compact faster machines used by people for a multitude of activities. Thus, now, although computers are still used in accounting and by scientists, computers are also used by other professions and even by individuals for home use. Increasing speed of computers has lead to uses of computers for graphically intensive applications such as for automated design or computer animation.
As computers continue to increase in speed, computers will be able to perform more functions than currently performed due to current limitations on processor speed. Furthermore, increased computer speed will allow for activities currently performed by computers to be improved. For example, increased computer speed will not only result in quicker rendering of graphics, it will also result in the ability to render graphics and animation in much finer detail than is currently available.
There are, however, many problems that must be overcome in order to increase the speed and performance of computers, or for that matter, in other type of data processing systems. One problem is that when data is driven at an increased frequency (faster speed), that over long lossy transmission media, such as may be encountered in the busses connecting various chips or components of a data processing system, that higher frequency components of the data are attenuated resulting in pulse width distortion and pulse amplitude reduction. The result is added jitter and a smaller eye opening. An eye opening, as is well known in the art, is a graphical representation of the window of time in which data is valid and may be interpreted correctly by a logic element. These problems result in an inability in components receiving the data to determine whether the data is a logical one or zero, thereby inducing errors in calculations performed by the data processing system. Therefore, it would be desirable to have a data driver for driving data off a chip that results in an increased eye opening thus allowing data to be driven at a higher frequency.
The present invention provides an improved data driver, method, and system for driving data with an improved slew rate and eye opening. In one embodiment, the data driver includes a non-precompensating data driver and a precompensating data driver. The non-precompensating driver generates a non-precompensating output data pulse corresponding to input data. The non-precompensating data driver generates a pulse in response to every input data bit received. The precompensating driver generates the precompensating pulse only in response to a transition from one data state to a second data state between consecutive data bits. The precompensating data pulse is shorter in duration than the non-precompensating output data. The output data from the data drive is the sum of the non-precompensating output data pulse and the precompensating output data pulse.